The present invention relates to high-temperature chemical reactions and, more particularly, to diesel particulate filters.
Diesel engines commonly emit exhaust containing fine organic particulate matter that should be removed prior to releasing the exhaust into the surrounding environment. Currently, removal of this particulate matter is performed by in-cylinder methods, where particulate matter is inhibited from forming during the combustion process, or by after treatment devices, where already-produced particulate matter is reduced or converted to an acceptable form of waste.
Typical after treatment devices include, for example, diesel particulate filters, diesel oxidation catalysts, and continually regenerating filters. When using after treatment devices, sometimes the exhaust needs to attain a minimum operating temperature, or critical temperature, to ensure proper functioning and operation of the devices. For example, carbon particulate matter can typically sustain an oxidation reaction between about 500° C. and 800° C. This temperature may be influenced by the presence of a catalyst, the desired reaction, and/or the exact chemical species being reacted. In addition, the completeness of the reaction may be influenced by the amount of time at the critical temperature, the chemical compound of the species being reacted, and the availability of reactants (e.g., oxygen) at the reaction site.
If the diesel exhaust does not reach this critical temperature, the after treatment devices should be periodically heated. In such scenarios, extra energy is required and expended in order to reach the critical temperature. For example, heat may be applied to the exhaust flowing into the after treatment devices or directly applied to an active surface or substrate within the devices. However, such an addition of heat can increase fuel consumption and/or add complexity to the after treatment devices.